Insulator



June 10, 1930. MILLER 1,763,171

INSULATOR Filed Feb. 19, 1927 WITNESSESZ 416 M INVENTOR Ff ed efl C/l M 7/6? ATTORNEY Patented June 10, 1930 IREDERIC H. MILLER, OF WILKINSBURG,

PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANLA INSULATOR Application med liebruary 19, 1927. Serial No. 169,488.

My invention relates to insulators and particularly to insulators that are adapted for high-voltage service.

One object of my invention is to provide an insulator of the above-indicated character that shall be simple and durable in construction, economical to manufacture and effective in its operation.

Another object of my invention is to provide a high-voltage tension insulator that shall have a sectionalized main dielectric body portion simulating a solid rod in Which the sections shall be under compression forces.

This invention is an improvement upon the invention set forth in my copending application, Serial No. 169,487, filed Feb. 19, 1927 for an insulator, to which reference may be had for a better understanding of the present invention.

Also, in copending application Serial No. 548,818, filed April 1, 1922, by H. B. Smith and assigned to the Westinghouse Electric & Manufacturing Company, is set forth an insulator which utilizes, to substantially maximum advantage, the insulating characteristics of a long straight rod. 4

The present invention relates to a rod for use in an insulator of the above-mentioned type.

I11 the manufacture of porcelain and other refractory articles, difficulties in firing are sometimes encountered with products of cer-v tain sizes and wall thicknesses, especially in those of relatively great masses of the material.

However, because such refractory material has inherent electrical advantages over wood and other materials, especially in outdoor high-voltage service, I desire to overcome the above-mentioned difficulties and to permit the use of a relatively massive rod of refractory material.

To accomplish that purpose, I propose the use of a sectionalized rod of such construction as to provide substantially the electrical characteristics of a rod consisting of a single homogeneous mass of the material, but which, at the same time, shall be materially stronger and be proof against damage from longitudinal and lateral or bending stresses.

Accordingly, in practicing my invention, I provide a refractory insulating structure that, in appearance and operation, is very similarto a single-piece rod, but that is made up of longitudinal sections which are so connected as to greatly improve the mechanical strength thereof and to have substantially the same electrical characteristics as a homogeneous insulating rod.

Fig. 1 of the accompanying drawing is a longitudinal side View, partially in elevation and partially in section, of an insulator embodying my invention, and

Fig. 2 is a sectional view taken along the line II-II of Fig. 1.

The device comprises, in general, upper and lower terminal structures 2 and 3, respectively, that are joined by the insulating rod structure 4 of my invention.

As set forth in the above-mentioned copending application, the terminal members 2 and 3 are so constructed and related to each other and to the rod 4 as to prevent concentration of the electrostatic field at any point, to Widely distribute the field at all points and to cause it to have a materially weakened central portion through which the rod 4 extends.

These features are obtained by having widely rounded portions 5 and 6 on the members 2and 8, respectively, that are laterally spaced from the rod and disposed inwardly therealong from the end portions of the member 4, thus causing the field to extend between the terminal members 2 and 3 in the form of a tube having a greatly weakened central portion.

The rod 4 comprises a plurality of axially alined insulating blocks 7 that are preferably of uniform cylindrical form and constructed of refractory insulating material, such as porcelain or glass.

The adjacent ends of each pair of the blocks 7 are preferably countersunk to provide recesses 8 wherein heads or nuts 9 on the ends of rods 10 are disposed.

While other combinations may be employed, the structure, as shown, embodies a pair of the rods 10 for connecting each pair of the blocks 7. The successive pairs of rods 10 are angularly displaced about the longitudinal axis of the rod 4 and longitudinally oifset with respect to each other so that, while all of the blocks 7 are under compressionload forces and the rod 4 is substantially as strong as the tensile stren th of the rods 10, there is no continuous conducting path along the rods 10 between the terminals 2 and 3, and the insulating value of the blocks 7 is retained.

The rods 10 are preferably provided with insulating sleeves 11 as protection between each set or pair of the rods 10 and the heads or nuts 9 of the alternate sets of rods 10 in the recesses 8.

Insulating barriers or plates 12 are also preferably disposed laterally across the recesses 8 to provide separate insulating compartments for the heads 9 of alternate sets of the rods 10 and to provide a slight lateral or bending resiliency to the rod as a Whole.

The relation of the rods 10 to each other and to the blocks 7 places the blocks in compression and, since the metal interconnecting parts are completely submerged by the insulating material and there are no metal or other elements extending continuously through the blocks 6 from the terminal 2 to the terminal 3, the electrical characteristics of the device are not materially changed from what they would be if the structure were entirely of insulating material.

IVhile I have shown and described a particular form of my invention, changes may be efiected therein without departing from the spirit and scope thereof as set forth in the appended claims.

I claim as my invention:

1. An insulator comprising a pair of endto-end related insulating units having the adjacent ends thereof countersunk to form a recess, amemberextending through saidunits to hold the same together, an insulating sleeve on said member in said recess, a laterally-extending insulating barrier dividing said recess into two compartments, and a member extending through each of the units having an enlarged head in one of said compartments.

2. An insulator comprising end-to-end related insulating units having adjacent ends constructed to form a recess, a member extending through said units to hold the same together, an insulating barrier dividing said recess into compartments, and a member extending through each of the units having an enlarged head in one of said compartments.

3. An insulator comprising a pair of endto-end related insulating units having adjacent ends constructed to form a recess, a member extending through said units to hold the same together, an insulating sleeve on said member extending through said units and said recess, a laterally-extending insulating barrier dividing said recess into two compartments, and a member extending through each 

